I found that Flash acts really funny with 310.14. Sound doesn't play unless I am on another workspace. When I switch back, so that I can see the video sound cuts out. Downgrading to 304.60 solved this problem.

I'm on Ubuntu 12.10 and have Flash 11.2.202.243, Firefox 16.0.1 and Nvidia drivers 310.14 (from xorg-edgers PPA), and I encountered no such issues. My display is hooked up via DVI and audio is obtained from the usual analog out jacks.

Another possibility is that it's a Fedora specific issue. Do other Fedora users have the same issue?